Farm Equipment - 200 - Oil in Coolant

Print Page | Close Window

200 - Oil in Coolant

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=139383
Printed Date: 28 Aug 2025 at 9:55am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: 200 - Oil in Coolant

Posted By: Dan (SE MI)
Subject: 200 - Oil in Coolant
Date Posted: 13 Jun 2017 at 11:36am

We have a 200 that appears to be putting oil in the coolant (not coolant in the oil). It does not seem to be severe, but the coolant went from appearing clean to having an oil film at the fill cap after a few hours use. At the same time, the engine oil level went down slightly. What are the typical failure modes that may cause this? It was purchased on an auction earlier this spring, so I do not have any history on it. Judging by the RTV, I believe that the oil cooler has been off recently. I assume this was done in an attempt to repair or investigate the issue. Overall, the tractor appears to be well maintained and in nice shape. It starts and runs well and other than this issue, everything else seems to be functioning correctly. Fortunately we assume things might crop up with auction purchases, so we bid appropriately.

Replies:

Posted By: DrAllis
Date Posted: 13 Jun 2017 at 12:23pm

Out of the dozens I've ever fixed like this, it's never been the oil cooler, always sleeve O-rings or pin holes in the sleeves. For proper diagnosis, drop the oil pan and leave coolant (not straight water---50/50 antifreeze) in the engine and pressurize the cooling system to no more than 12 psi and let it sit overnite to see where it's coming from. Sometimes the block heater needs to be plugged in to warm things up to find the leak, but that is rare. Oil pan can be removed by swinging axle rear pivot block down or remove it while jacking up underneath the bell housing. Drop the oil pan and drop oil pump suction tube into the pan and worm them out of there. If engine needs sleeves you can then roll the front axle out from underneath it to work on engine, so PLAN AHEAD and park it where it can sit and be repaired.

Posted By: Dan (SE MI)
Date Posted: 13 Jun 2017 at 2:56pm

Thanks for the input. I have been through o-ring/liner issues in the past and those failures resulted in coolant in the oil, which is the opposite of what I am seeing. I guess I can’t picture how the oil would have enough pressure to get into the coolant at that interface. None the less, the oil and coolant are getting in contact somehow so your suggestion could certainly provide insight.

Posted By: DrAllis
Date Posted: 13 Jun 2017 at 4:05pm

Let the tractor sit overnite and very slowly remove the drain plug to the oil pan. If there's coolant/antifreeze it will be on the bottom of the pan and will show up at the drain plug. Pull off the breather hose at the valve cover and see if there's any white shaving cream looking stuff. Both of these are signs of coolant in the oil even tho you don't think there is.

Posted By: MACK
Date Posted: 13 Jun 2017 at 10:32pm

Dr. reread the post. He is getting oil in coolant not coolant in oil.
Oil cooler is the only place that oil can get into coolant. MACK

Posted By: DrAllis
Date Posted: 14 Jun 2017 at 7:22am

I have had a couple that did both oil in coolant and coolant in the oil (even tho customer didn't think it was in the oil) and it was sleeve O-rings. As with so many posts on here, the amount of oil in the coolant and whether or not there is coolant in the oil is the issue, and I'm not there looking at it. If the radiator cap is boiling oil out when being used, it's the oil cooler or a cracked block/cyl head. If it is slight oil residue in coolant, my money says there's coolant in the oil too. That's why I said to check for coolant in the oil as well. It's funny the oil cooler appears to have been worked on and there's oil in the coolant and it was for sale. Was the cooler removed and tested and was deemed to be OK ???

Posted By: Dan (SE MI)
Date Posted: 14 Jun 2017 at 11:10am

Thanks for the responses. I agree, with evidence of oil in the coolant, coolant in the oil is certainly a possibility. I will follow up on the Dr.’s suggestions to check for that. The fact that the oil cooler has been worked on recently and it was up for sale probably does indicate that the issue is elsewhere, but you never know. Fortunately we bought it right with no intention of relying on it as a primary tractor. If the investigation gets more involved it might have to wait until we have more time to work on it. Whatever happens I will try and provide an update on what we find. Thanks again Dr. and Mack. I greatly appreciate your input.

Posted By: FREEDGUY
Date Posted: 26 Jun 2017 at 9:53pm

Dan,were you able to locate the coolant issue?

Posted By: Dan (SE MI)
Date Posted: 28 Jun 2017 at 11:42am

We pressure checked the oil cooler, from the oil side, with shop air and didn’t find anything. While still a possibility, I doubt it is the cooler. Most likely an issue in the block or head. Working from easiest to more involved, our next step will be to check the head gasket. Unfortunately I am not sure when we will be able to get to that. It is parked for now. Like everyone else, too many projects and too little time. I will report back when we find something.

Posted By: DrAllis
Date Posted: 28 Jun 2017 at 11:57am

If you pull the head first, you'll not be able to pressurize the cooling system to check sleeve O-rings. When in doubt, I pull the pan, pressurize the cooling system and wait and see where it's coming from. If it's a sleeve O-ring, you'll see it. If it's a head gasket, it will be coming from somewhere else instead of the sleeve O-ring area.